Well, "revolutionary" might be overstating it but we won't know until the reviews are in. From this press release:

SAN DIEGO, Aug. 5, 2009 – Sony today announced two new Cyber-shot® cameras (DSC-TX1 and DSC-WX1 models) that provide unprecedented advances in low-light performance with approximately twice the sensitivity of cameras with traditional image sensors.

These Cyber-shot cameras are the first to employ Sony’s new “Exmor R” back illuminated CMOS sensor technology to improve shooting in low-light scenarios, enhancing image clarity and drastically reducing grain.

There's much more detail in the press release about the background to this backlit sensor technology (similar technology has been used in astronomical sensors for some time) or you can view the individual product pages by clicking on the images below.

I've read comments that say they do not expect this technology to help DSLRs much. The reason they're useful in compacts is due to the very small pixel pitch of compact sensors. The circuitry that goes before the light sensitive layer really affects the efficiency of light transmission. With DSLRs on the other hand, the pixel pitch is a lot larger. Thus the circuitry that goes before the light sensitive layer doesn't obscure as much light.

All this is just speculation and hearsay for now. I guess we'll only know for certain what kind of noise performance we get from the new sensors. To be perfectly honest, even if they make no difference to DSLRs it could open up a new generation of good low light performing compacts and I could always use one of those

This was one of those "bah, I'll believe it when it makes production" kind of technologies for me and now it actually has! Can't wait to see the sample images, I hope the images are actually and improvement and this turns out to be more than just a marketing exercise.